Bispiperazido phosphorus polyamides

ABSTRACT

Novel polymers, useful as films or filaments, are prepared as by the reaction of a bispiperazidophosphosphorus compound with a reactive derivative of an acid.

BACKGROUND OF THE INVENTION

This invention relates to novel polymers and to a process for thepreparation thereof. These polymers are polyamides which containphosphorus atoms as part of the main polymer chain.

This invention also relates to shaped articles, such as films andfilaments, formed from these polymers.

The simplest polyamides are those obtained by the self-condensation oflactams, e.g. nylon-6 obtained from caprolactam, and those obtained bycondensing a diamine with a dicarboxylic acid or acid derivative, e.g.poly(hexamethylene adipamide) or nylon-66. Whilst simple polymers ofthis type have many advantages of strength and resistance to harmful anddegradative influences of many types, they also have many shortcomings,and even disadvantages, and continual effort has been expended both onimproving the properties the polyamides intrinsically possess, and onimparting properties which the simple polyamides do not possess.

For instance, polyamides can be synthesized from mixtures of amines oracids, or substitution reactions can be carried out on previouslyprepared polyamides, whereby desired substituent groups can be appendedto the polyamide chains, so as to provide the polyamides with desiredproperties. For instance, groups can be added which enable dyestuffs tobind tightly to polyamide chains.

An article by Bello et al. in Macromolecules Vol. 3, pages 98- 100(1970) describes the preparation of polymers having repeating units ofthe formulae ##STR1## by the reaction of phosphoric dimethylamidobispiperazide ##STR2## with, respectively, piperazine-1,4-dicarbonylchloride and oxalyl dichloride.

The object of the present invention is the synthesis of novelphosphorus- and nitrogen-containing polymers. A further object of thisinvention is the synthesis of polymers which are inherentlyflame-resistant or non-flammable.

STATEMENT OF THE INVENTION

The present invention provides polymers containing repeating units ofthe formula ##STR3## wherein X is absent or represents an oxygen orsulphur atom, or a group of the formula ═ N--R, in which R represents ahydrogen, an aliphatic, cycloaliphatic or aromatic group, or aheterocyclic group;

Y represents an aliphatie, cycloaliphatic or aromatic hydrocarbon groupor a heterocyclic group; a group of the formula --NR₂ in which eachgroup R has the meaning given above, or the two groups R, together withthe nitrogen atom to which they are attached, represent a N-containingheterocyclic ring; a group of the formula - OR in which R has themeaning given above; or a group of the formula ##STR4## R¹, R² and R³,which may be the same or different, each represents a substituent on thepiperazine ring,

R⁴ represents a hydrogen atom or a substituted or unsubstitutedaliphatic, cycloaliphatic, or heterocyclic radical or heterocyclicgroup, an acyl group, a sulphonyl group; or a substituted orunsubstituted carbamoyl group;

n¹, n² and n³, which may be the same or different, each represents 0 oran integer; and

Z represents a group of the formula C ═ O, C ═ S or --CO--CO--; anorganic dicarboxylic group of the formula

    --CO--R.sup.5 --CO--

in which R⁵ represents a substituted or unsubstituted aliphatic,cycloaliphatic or aromatic hydrocarbon radical, or a heterocyclicradical, or a group of the formula

    --CO--Ar.sup.1 --Q--Ar.sup.2 --CO--

in which Ar¹ and Ar², which may be the same or different each representsan arylene group, and

Q represents a group of the formula --O--, --S--, --SO--, --SO₂ --,##STR5## --NR⁶ -- (wherein R⁶ represents an aliphatic, cycloaliphatic oraromatic radical or heterocyclic radical), --SiR₂ ⁶ --, or is a divalentaliphatic or cycloaliphatic group; a group of the formula ##STR6## inwhich X, Y and R⁵ have the meanings given above -- a group of theformula --SO₂ --, --SO--, --SO₂ --R⁵ --SO₂ --, --SO--R⁵ --SO-- or --SO₂--R⁵ --SO-- in which R⁵ has the meaning given above; or a group of theformula ##STR7## or a group of the formula ##STR8## but wherein Y cannotbe dimethylamino when X represents oxygen and n¹ and n² are both zero.

In the formulae in this specification, it will be apparent that theexpression "X is absent or represents . . ." may be equivalentlyexpressed by the expression "(X)_(a) wherein a is 0 or 1".

The present invention also provides a process for the production of suchpolymers which comprises reacting a bispiperazide of the formula##STR9## in which R¹, R², X, Y, n¹ and n² have the meanings given above,with a reactive derivative of an acid, having the formula

    R.sup.7 --Z --R.sup.8                                      VII

in which Z has the meaning given above, and R⁷ and R⁸, which may be thesame or different, each represents a halogen atom or a hydroxy or alkoxygroup.

DESCRIPTION OF THE INVENTION

According to one preferred embodiment of the invention, n¹ and n² bothrepresent 0.

According to another preferred embodiment of the invention, X representsoxygen or sulphur, and Y represents an alkoxy, aryloxy or dialkylaminogroup.

According to a further preferred embodiment of the invention Zrepresents a diacyl radical derived from an aliphatic or aromaticdicarboxylic acid.

According to yet another preferred embodiment of the invention, R⁷ andR⁸ each represents chlorine.

If desired, it is possible to carry out polycondensation reactions inwhich either or both of the bispiperazide VI and the compound of formulaVII forms part of a mixture with another amine or acid derivativerespectively. These other amines or acids may have the same generalformula, or the amine may be another polyamide-forming amine.

In the present invention, the symbol X can represent an oxygen orsulphur atom or a group ═ NR, or it can be absent. The bispiperazidesand trispiperazides, used in the process according to the invention aretherefore amides of phosphoric acid (when X represents oxygen),thiophosphoric acid (when X represents sulphur), phosphorimidic acid(when X represents ═ NR), and phosphorous acid (when X is absent).

The symbol Y can represent a group of the formula: ##STR10## in whichcase, the compounds used in the process according to the invention aretrispiperazides. When Y has one of its other meanings, the compounds arebispiperazides.

Y can for example represent a substituted or unsubstituted hydrocarbongroup which can be of aliphatic, cycloaliphatic or aromatic nature.Examples of suitable aliphatic groups are alkyl, such as methyl, ethyl,propyl, butyl, octyl, dodecyl, or octadecyl; alkenyl, such as allyl; oralkynyl, such as propargyl.

Examples of suitable cycloaliphatic groups are cycloalkyl, such ascyclohexyl, tetrahydronaphthyl or decahydronaphthyl; and cycloalkenyl,such as cyclohexenyl.

Examples of suitable aromatic hydrocarbon groups are aryl groups, suchas phenyl, naphthyl, biphenyl, or phenanthryl; aralkyl, such as benzyl,or phenylethyl; and alkaryl, such as tolyl, dimethylphenyl,trimethylphenyl, cumyl, or p-octylphenyl.

Y can alternatively represent a heterocyclic group, linked to thephosphorus atom through a carbon atom, as in the tetrahydrofurfuryl or2-pyridyl radicals.

Y can also represent a group of the formula --NR₂, in which each Rrepresents a hydrogen atom, or an aliphatic, cycloaliphatic, or aromatichydrocarbon group or a heterocyclic group. Examples of these hydrocarbongroups or heterocyclic groups are given above. Specific examples ofsuitable amino radicals are dimethylamino, diethylamino, dipropylamino,dibutylamino, monomethylamino, monoethylamino, monododecylamino,mono-(C₁₀₋₁₄) alkylamino, monooctadecylamino, anilino, p-dodecylanilino,and N-butylanilino.

Alternatively, both symbols R, and the nitrogen atom to which they areattached, can together represent a heterocyclic radical linked to thephosphorus atom through the nitrogen atom. Examples of such groups aremorpholino, piperidino, tetrahydroquinolino, pyrrolidino etc. Thecompounds in which Y represents a further piperazino group are, ofcourse, a special instance of this.

Y can also represent a group of the formula --OR in which R has themeaning given above. Examples of such groups are alkoxy, such asmethoxy, ethoxy, propoxy, butoxy, dodecyloxy and octadecyloxy; andaryloxy such as phenoxy, tolyloxy, or benzyloxy.

Any of the above radicals can if desired, be substituted. The onlylimitation upon the nature of the substituents is that they should beinert under the conditions of the reaction employed in synthesizing thecompound.

In the groups of the formula: ##STR11## R¹, R² and R³, which may be thesame or different, represent substituents on the piperazine ring. Hereagain, the only limitation upon the nature of the substituent is that itshould be inert under the conditions of the reaction used to synthesizethe compound. The substituent can, for example, be one of the groups setout above for Y, provided that such a group is inert. When present, itcan for example be an alkyl group, such as a methyl group.Alternatively, the substituent can have a meaning not set out above,insofar as it might be an appropriate group for attachment tophosphorus: for example, an oxo group. Specific examples of substitutedpiperazine groups are 2,5-dimethylpiperazine and 2,5-dioxopiperazinogroups, n¹, n² and n³, which can be the same or different, eachrepresents 0 or an integer, preferably 0, 1 or 2: R⁴ can represent ahydrogen atom or a substituted or unsubstituted aliphatic,cycloaliphatic or aromatic hydrocarbon group or a heterocyclic group.Examples of suitable groups are set out above. Specifically preferredgroups R⁴ include alkyl, such as methyl, ethyl, phenyl, and substitutedgroups such as β-cyanoethyl and β-carbethoxyethyl. R⁴ can also representan acyl group, e.g. of an aliphatic, cycloaliphatic, aromatic orheterocyclic carboxylic acid, such as acetic, propionic, butyric orstearic acid, cyclohexane carboxylic acid, benzoic acid, toluic acid,nicotinic acid or a methylnicotinic acid. Alternatively R⁴ can representa sulphonyl group, for example a methane sulphonyl, benzene sulphonyl ortoluene sulphonyl group. R⁴ can also represent a substituted carbamoylgroup --CO--NHR wherein R has the meaning given above. An example ofsuch a group is phenylcarbamoyl.

These piperazide compounds are described in co-pending Application Ser.No. 628,288 filed Nov. 3, 1975.

They can readily be prepared by reacting a compound of the formula##STR12## in which X and Y have the meanings given above and Halrepresents chlorine or bromine, with a piperazine derivative of theformula ##STR13## in which R¹ and n have the meanings given above. Thisreaction can conveniently be carried out in an inert solvent, e.g.benzene, toluene or xylene at an elevated temperature, e.g. 60 to 80° C.

In the acid moiety of the polymers, Z can, according to one embodimentof the invention, represent a group of the formula >CO, >CS or--CO--CO--, in which case the polymers are, respectively, polyamides ofcarbonic, thiocarbonic and oxalic acid.

According to another embodiment of the invention, the acids, which canbe employed as such, or as their esters or halides, in the production ofthe polymers, have the formula

    HOOC-- R.sup.5 -- COOH                                     XI

in this formula, R⁵ represents a substituted or unsubstituted aliphatic,cycloaliphatic, aromatic radical, or a heterocyclic radical. Suitablealiphatic radicals are alkylene radicals, such as polymethyleneradicals; alkylidene radicals, such as ethylidene or isopropylideneradicals; alkenylene radicals, such as --CH═CH--; and alkynyleneradicals, such as --C═C--. Examples of acids in which R⁵ represents amethylene or polymethylene chain include malonic, succinic, glutaric,adipic, pimelic and sebacic acids. Acids in which R⁵ is alkylidene are,e.g. monomethylmalonic, dimethylmalonic and α-methylsuccinic acid. Acidsin which R⁵ is alkenylene include maleic and fumaric acids. Acids inwhich R⁵ is alkynylene include acetylene dicarboxylic acid.

Suitable cycloaliphatic acids are saturated or unsaturated acids, suchas cyclohexane-1,2-dicarboxylic acid and cyclohexene-1,2-dicarboxylicacid.

Suitable aromatic acids are those in which R⁵ represents an o-, m- orp-phenylene group, a naphthylene group or a biphenylene group, e.g.phthalic acid, isophthalic acid, terephthalic acid,naphthylene-1,8-dicarboxylic acid or biphenyl-4,4'-dicarboxylic acid.

Another group of acids that can be employed in the process according tothe invention have the general formula

    HOOC-- Ar.sup.1 -- Q-- Ar.sup.2 -- COOH                    XII

in which Ar¹ and Ar², which may be the same or different, eachrepresents an arylene group (which may be substituted or unsubstituted)and Q represents a group of the formula --O--, --S--, ##STR14## whereinX and Y have the meanings given above, --SO--, --SO₂ --, NR⁶ or SiR₂ ⁶(wherein R⁶ represents an aliphatic, cycloaliphatic or aromatic radicalor heterocyclic radical), or Q can represent a divalent aliphatic orcycloaliphatic group. Examples of such acids are diphenylether-4,4'-dicarboxylic acid, diphenyl sulphide-4,4'-dicarboxylic acid,diphenyl sulphoxide-4,4'-dicarboxylic acid, diphenylsulphone-4,4'-dicarboxylic acid, diphenyl methylamine-4,4'-dicarboxylicacid, diphenyl dimethylsilane-4,4'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, and2,2-diphenylpropane-4,4'-dicarboxylic acid.

Another group of acids has the formula ##STR15## in which X, Y and R⁵have the meanings given above. Examples of such acids include monophenylphosphate, monoacetyl phosphate, monophenyl phosphite and N"-methylmonophenyl phosphoamidate.

Yet another group of acids is constituted by the sulphur-containingacids

Ho.so₂.oh, ho.so.oh, ho.so₂.r⁵.so₂ h,

ho.so.r⁵.so.oh and HO.SO₂.R⁵.SO.OH,

i.e. sulphuric acid, sulphurous acid, hydrocarbon disulphonic acids(e.g. butane-1,4-disulphonic acid, or benzene disulphonic acid),hydrocarbon disulphinic acids and hydrocarbon monosulphonicmonosulphinic acids.

In another group of polymers, the group Z has the formula ##STR16## Insuch groups, R⁶ is preferably methyl or phenyl.

It is also possible to use mixed bifunctional acids ##STR17## in whichX, Y, R⁵ and R⁶ have the meanings given above.

Although the polymer-forming reaction according to the invention can becarried out using an acid or ester of the formula

    R.sup.7 -- Z-- R.sup.8

in which R⁷ and R⁸ each represents a hydroxy or alkoxy group, it is mostconveniently carried out using a dihalide, particularly a dichloride ofthe formula ZCl₂.

Reaction between the dichloride and the piperazido reactant can becarried out in homogeneous solution in a polar organic solvent, or as aninterfacial reaction employing two immiscible solvents, one of which isgenerally water.

Suitable polar organic solvents include carbon tetrachloride,chloroform, dimethyl formamide (DMF) and dimethyl sulphoxide (DMSO). Forgood results, it is desirable that an acid-acceptor should be present inorder to take up the HCl which is generated as the reaction progresses.Organic bases, e.g. triethylamine are preferably employed for thehomogeneous polycondensation, and inorganic bases, e.g. sodium hydroxideor potassium hydroxide, are preferably employed for the interfacialpolycondensation.

The polyamides according to the invention can be cast from solution intofilms, or can be formed into shaped articles, such as filaments.According to one embodiment of the invention, a yarn can be pulleddirectly from the interface when polycondensation is carried out inheterogeneous systems.

The solid polyamides are flame-retardant or non-burning, and can beused, by themselves or in combination with other polyamides to provideflame-retardant or non-burning polymers.

Practice of the process of this invention will be apparent to thoseskilled in the art from the following illustrative examples.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Typical polycondensation procedures, on a laboratory scale are asfollows:

EXAMPLE I 1. HOMOGENEOUS POLYCONDENSATIONS

Using chloroform (CHCl₃) or dimethylformamide (DMF) as solvent, suchpolycondensations have been carried out according to the followingstandard procedure: To 0.005 mole of the bispiperazidophosphoruscompound and 0.010 to 0.012 mole of triethylamine, dissolved in 25 ml ofdry solvent, is added, in one portion at room temperature with gentlestirring, 0.005 mole of the diacid chloride dissolved in 25 ml of drysolvent. Usually a temperature rise from 20°-22° C to 30°-35° C within 5minutes was observed, and the mixture was stirred for 15 to 60 minutes.

The reaction mixture was worked up as follows:

a. If DMF was used as solvent, the reaction mixture was added dropwisewith stirring to 600 ml of water. If the polyamide did not precipitate,dry ice was added to provoke precipitation.

The precipitated polyamide was filtered off, washed with water, anddried in vacuo over P₂ O₅ at 40°-70° C/1 mm.

b. If CHCl₃ was used as solvent, the reaction mixture was precipitatedwith petroleum ether or n-hexane (600 ml) and the polymer was filteredoff, washed with water to remove triethylamine hydrochloride and driedin vacuo over P₂ O₅ at 40°-70° C/1 mm. Sometimes the polyamide became asticky mass on washing with water. When this happened, the polyamide wasdissolved in chloroform (30- 50 ml), ethanol and benzene were added andthe water and solvents were distilled off under reduced pressure at60°-100° C. The remaining polyamide was redissolved in chloroform (30ml), and precipitated with petroleum ether or n-hexane (500- 600 ml) or,if precipitation was not possible, the polyamide was isolated by freezedrying from a chloroform solution.

EXAMPLES II-III II. HETEROGENEOUS (INTERFACIAL) POLYCONDENSATIONS

The systems CHCl₃ /H₂ O and CCl₄ /H₂ O were used according to followingstandard procedure:

To a solution of 0.005 mole of the bispiperazidophosphorus compound and0.012 mole of potassium hydroxide in 40 ml of water, was added in oneportion, at room temperature and with vigorous stirring, a solution of0.005 mole of the diacid chloride in 40 ml of chloroform or carbontetrachloride, and the mixture was stirred for 15 to 30 minutes.

When the reaction was carried out using 0.10 mole of thebispiperazidophosphorus compound and 0.1 mole of the diacid chloride in600 to 750 ml of solvent and 200 to 270 ml of water, the temperature ofthe reaction mixture rose from 20°-22° C. to about 35° C. within 5minutes, due to the heat evolved.

In the mixture CCl₄ /H₂ O, the polyamide precipitated as it was formed,and formed a thick swollen lump, but in the system CHCl₃ /H₂ O, thepolymer remained dissolved. In general there was no considerabledifference between the results (yield-molecular-weight) obtained in thetwo solvent systems. An emulsion was, however, often formed when usingthe CHCl₃ /H₂ O system, necessitating the use of different methods forisolating the polyamides from the various reaction mixtures:

1. From a CCl₄ /H₂ O mixture.

The precipitated polyamide was filtered off, cut into small pieces,washed with water and dissolved in 60 to 100 ml of chloroform.

EXAMPLE II

This solution was washed twice with 70 to 100 ml of water, to removeinorganic and organic potassium salts, and concentrated to about 30 mlin vacuo, and the polyamide was isolated by precipitation with 600 ml ofpetroleum ether or n-hexane. Then it was filtered off and dried over P₂O₅ in vacuo (1 mm) at 40°-70° C.

EXAMPLE III 2. From a CHCl₃ /H₂ O mixture.

a. When no emulsion was formed, or when separation between thechloroform and the water layer still occurred, the organic layer wasseparated, washed twice with 70- 100 ml of water to remove potassiumsalts, and concentrated in vacuo to about 30 ml, and the polyamide wasprecipitated by pouring this solution into 600 ml of petroleum ether,filtered off and dried.

Sometimes an additional amount of polymer could be recovered byextracting the water layer and the wash water with chloroform, and bypouring the water-washed and concentrated chloroform solution intohexane.

b. When the separation of the layers was too difficult, or when anemulsion was formed, the chloroform was stripped off in a thin filmevaporator at temperature 60°-90° C/20 mm and the remaining water wasdecanted from the precipitated polymer, which was rinsed with 100 ml ofwater and redissolved in 60 to 100 ml chloroform. This solution waswater-washed and concentrated, and the polyamide was precipitated with600 ml of n-hexane, filtered off, and dried.

If during purification of the polyamide by washing a chloroform solutionwith water, an emulsion was again formed, the chloroform was distilledoff at reduced pressure, the supernatant water was decanted from theprecipitated polymer, the rest of the water was removed as an azeotropewith some added alcohol and benzene. The remaining polyamide was furthertreated as above.

If precipitation of the polymer was not possible, the polyamide wasisolated by freeze drying from chloroform solution. The ratio of organicsolvent: water can be varied over a wide range, e.g. 1:1 to 3:1, with nosubstantial variation in the results obtained.

Details of small-scale syntheses of polyamides, using terephthaloylchloride and sebacoyl chloride, with various bispiperazido compounds areset out in Table 1 below. The solvent systems yields and reducedviscosity (a measure of molecular weight) are also set.

The polyamides were all white solids and several were slightlyhygroscopic. The reduced viscosity was measured in 0.4% by weightsolution in CHCl₃ at 25° C.

                                      TABLE 1                                     __________________________________________________________________________     ##STR18##                                                                     ##STR19##                                                                                       Interfacial   Viscosity                                    POLYAMIDE          polycondensation                                                                       Yield                                                                              η red                                    No.                                                                              X Y      R      system.sup.1                                                                           %    (in dl/g)                                    __________________________________________________________________________    IV O OC.sub.6 H.sub.5                                                                     C.sub.6 H.sub.4 -(p)                                                                 CHCl.sub.3 /H.sub.2 O                                                                  103.sup.a                                                                          0.72                                                                     102.7.sup.a                                                                        1.10                                         V  O N(C.sub.3 H.sub.7).sub.2                                                             C.sub.6 H.sub.4 -(p)                                                                 CHCl.sub.3 /H.sub.2 O                                                                  78.8 0.19                                         VI S OC.sub.2 H.sub.5                                                                     C.sub.6 H.sub.4 -(p)                                                                 CHCl.sub.3 /H.sub.2 O                                                                  100  0.475                                        VII                                                                              S OC.sub.6 H.sub.5                                                                     C.sub.6 H.sub.4 -(p)                                                                 CHCl.sub.3 /H.sub.2 O                                                                  96.0 0.42                                         VIII                                                                             O OC.sub.6 H.sub.5                                                                     (CH.sub.2).sub.8                                                                     CCl.sub.4 /H.sub.2 O                                                                   88.1 0.61                                         IX O N(C.sub.3 H.sub.7).sub.2                                                             (CH.sub.2).sub.8                                                                     CCl.sub.4 /H.sub.2 O                                                                   78.6 0.44                                         X  S OC.sub.2 H.sub.5                                                                     (CH.sub.2).sub.8                                                                     CHCl.sub.3 /H.sub.2 O                                                                  97.3 0.425                                        XI S OC.sub.6 H.sub.5                                                                     (CH.sub.2).sub.8                                                                     CCl.sub.4 /H.sub.2 O                                                                   93.0 0.45                                         __________________________________________________________________________     .sup.1 KOH was used as HCl acceptor.                                          .sup.a Probably the polymer still contained some absorbed water.         

The polyamides had good solubility in chloroform and dimethyl formamide,some were soluble in methanol and ethanol, and a few in dioxane, benzeneand acetone. The polyamides were not soluble in carbon tetrachloride,petroleum ether, ether, or paraffinic oils.

The polyamides show, in general, melting temperatures in the range of150° to 280° C., and start to decompose at about 300° C. The polyamidesderived from sebacoyl chloride have lower melting and decompositiontemperatures than derivatives of terephthaloyl chloride. Details aregiven below in Table 2 which sets out results obtained by heating thepolyamides at a rate of 10° C. per minute in a capillary tube, and bydifferential thermoanalysis.

                  TABLE 2                                                         ______________________________________                                         ##STR20##                                                                                                   Decomp-                                                              Melting  osition                                        POLYAMIDE             Temp.    temp.                                          No.  X     Y           R        (° C)                                                                         (° C)                           ______________________________________                                        IV   O     OC.sub.6 H.sub.5                                                                          C.sub.6 H.sub.4 -(p)                                                                   250-270                                                                              340-350                                V    O     N(C.sub.3 H.sub.7).sub.2                                                                  C.sub.6 H.sub.4 -(p)                                                                   215-255                                                                              350-380                                VI   S     OC.sub.2 H.sub.5                                                                          C.sub.6 H.sub.4 -(p)                                                                   280-290                                                                              310-320                                VII  S     OC.sub.6 H.sub.5                                                                          C.sub.6 H.sub.4 -(p)                                                                   268-280                                                                              360-370                                VIII O     OC.sub.6 H.sub.5                                                                          (CH.sub.2).sub.8                                                                       170-190                                                                              260-300                                IX   O     N(C.sub.3 H.sub.7).sub.2                                                                  (CH.sub.2).sub.8                                                                       100-154                                                                              270-300                                X    S      OC.sub.2 H.sub.5                                                                         (CH.sub.2).sub.8                                                                       240-270                                                                              288-290                                XI   S     OC.sub.6 H.sub.5                                                                          (CH.sub.2).sub.8                                                                       210-230                                                                              360-380                                ______________________________________                                    

Film forming properties of the polyamides

Films cast from chloroform solutions of the polyamides, in general havea good appearance. They are colorless, flexible and non-burning orself-extinguishing when ignited in a Bunsen flame.

Polyamide films dissolve in 10 N sulphuric acid within a few hours, buthave good resistance to 0.1 N sulphuric acid in which they turn hazy andshow only small changes in weight when immersed for 6 to 14 days.

The polyamide films are resistant to caustic solutions; when immersed in10 N NaOH and in 0.1 N KOH at room temperature the film remainsunchanged or turn hazy; in some instances, small changes in weight areobserved.

The polyamide films seem unchanged on ageing, no change in appearance orsolubility in chloroform were observed on film strips which were exposedto daylight and air for several months.

Mechanical properties of the polyamides

Two polyamides, sample (IV) (X = O; Y = O--C₆ H₅ ; R = (C₆ H₄ --) η₀.4 =0.66 dl/g (CHCl₃ ; 25° C) and sample V (X = O; Y = N(C₃ H₇)₂ ; R = --C₆H₄ --) η₀.4 = 0.16 dl/g (CHCl₃ ; 25° C) were selected for testingbecause they represent extremes of molecular weight. Sample V wasmoulded (325° F; 163° C) directly from the powder since it darkenedseverely on roll milling. Sample IV was milled and moulded at 400° F(204.4° C). By minimizing processing times and temperatures, it waspossible to produce amber colored specimens. However they were verybrittle, which is likely due to their relatively low molecular weights.

On the other hand it was possible to produce polymer fibres byinterfacial spinning. The polymer film formed at the interface of acarbon tetrachloride solution of terephthaloyl chloride and an aqueousalkaline solution of phenyl bispiperazidophosphate could be pulled outfrom the mixture as a continuous strand. The polyamide strand wound upfrom the mixture had a reduced viscosity of 0.485 dl/g at 0.4% wt (CHCl₃; 25° C).

a. Homogeneous Reaction Systems. EXAMPLE 1: Preparation of polyamide IV.

To 0.005 mole (1.552 g) of phenyl bispiperazidophosphate and 0.01 mole(1.4 ml) of triethylamine in 25 ml of chloroform (free of ethanol) wasadded, in one portion at room temperature with stirring, 0.005 mole(1.015 g) of terephthaloyl chloride dissolved in 25 ml of chloroform.The reaction temperature rose to 35° C. within 5 minutes, and themixture was stirred for 15 minutes. From it the polyamide wasprecipitated by pouring the solution into 600 ml of vigorously stirredn-hexane. The polyamide was filtered off, throughly washed with waterand dried over P₂ O₅ at 70° C. in vacuo (1 mm). Yield: 2.092 g IV (95%);[η] = 0.425 dl/g; η_(red) = 0.46 dl/g (CHCl₃ ; 0.40 g/dl; 25° C).Melting range 258°-270° C; Decomposition temp. 350° C.

The polyamide could be cast from a chloroform solution to give acolourless, flexible film, which was non-burning.

EXAMPLE 2: Preparation of polyamide VII

To a solution of 0.005 mole (1.632 g) of phenylbispiperazidothiophosphate and 0.01 mole (1.4 ml) of triethylamine in 25ml of DMF was added, in one portion with stirring, 0.005 mole (1.05 g)of terephthaloyl chloride in 25 ml of DMF. The temperature rose from 22°C. to 35° C. within 5 minutes. The mixture was stirred for 5 minutes andkept at ambient temperature overnight, and was then poured into 600 mlof water. An emulsion was obtained, from which precipitation of thepolyamide was provoked by dry ice.

The polymer was filtered off, washed with water and dried at 70° undervacuum (1 mm) over P₂ O₅. Yield of VII: 2.007 g (87.9%); [η] = 0.13dl/g; η_(red) = 0.155 dl/g (0.4 g/dl; CHCl₃ ; 25° C). Melting range:268°-280° C; decomposition temperature 360° C. This polymer formed awhite-hazy, very brittle film, when cast from a chloroform solution.

EXAMPLE 3: Preparation of polyamide VIII

To a solution of 0.005 mole (1.552 g) of phenyl bispiperazidophosphateand 0.010 mole (1.4 ml) of triethylamine in 35 ml of chloroform wasadded, in one portion with stirring, 0.005 mole (1.066 ml) of sebacoylchloride in 45 ml of chloroform. The temperature rose from 22 to 32° C.and the mixture was stirred for 15 minutes, during which it remained aclear solution. The mixture was concentrated in vacuo and poured into600 ml petroleum ether. The polyamide precipitated as a white powder andwas filtered off. On washing with water it formed a sticky mass whichwas dried in vacuo over P₂ O₅.

The polymer was redissolved in chloroform and isolated by freeze dryingin the form of a white foam. Yield of VIII: 2.142 g (89.9%); [η] = 0.133dl/g; η_(red) = 0.145 dl/g (CHCl₃ ; 0.4 g/dl; 25° C). Melting range 70°-80° C; decomposition temperature 240°-250° C.

When cast from a chloroform solution, the polymer formed a colourlessflexible film which was non-burning.

b. Heterogeneous Reaction Systems. EXAMPLE 4: Preparation of polymer IV.

To a solution of 0.005 mole (1.015 g) of terephthaloyl chloride in 160ml chloroform was added, in one portion at room temperature withvigorous stirring, a solution of 0.005 mole (1.552 g) of phenylbispiperazidophosphate and 0.012 mole of potassium hydroxide in 72 ml ofwater, and the mixture was stirred for 30 minutes. A milky solution wasformed which was separated into a chloroform layer and a milky waterlayer in a separation funnel. The chloroform layer was water-washed, andchloroform and residual water were stripped off. The residue wasredissolved in 40 ml of chloroform and filtered, and the polyamide wasprecipitated by pouring this solution into 400 ml of n-hexane. Thepolymer was filtered off and dried in vacuo over P₂ O₅. Yield: 1.808 g[η] = 0.95 dl/g; η_(red) = 1.103 dl/g (CHCl₃ ; 25° C; 0.40 g/dl).Melting range 280°-285° C, decomposition temperature 360° C.

From the collected water layer and wash waters, chloroform wasevaporated by boiling. The precipitated polymer was filtered off, waterwashed, redissolved in chloroform, filtered and precipitated withhexane. An additional amount of 0.453 g of IV, η_(red) : 1.139 dl/g(CHCl₃ ; 0.4 g/dl; 25° C) was obtained.

Total yield: 2.261 g (102.7 %) (probably the polymer still containedsome solvent or absorbed water).

EXAMPLE 5: Preparation of polyamide VI

To a solution of 0.005 mole (1.015 g) of terephthaloyl chloride in 175ml chloroform at 55° C. was added, in one portion with stirring, 0.005mole (1.392 g) of ethyl bispiperazidothiophosphate and 0.012 mole ofpotassium hydroxide in 77 ml of water at 55° C. The mixture was stirredfor 30 minutes and the chloroform layer was separated from the milkywater layer. The latter was extracted with chloroform and the collectedchloroform solutions were washed with water. Chloroform and residualwater were stripped off under vacuum, the residue was redissolved in 30ml chloroform, filtered and poured into 600 ml hexane.

The precipitated polyamide was filtered off and dried. Yield: 2.05 g(100%) [η] = 0.447 dl/g; η_(red) = 0.475 dl/g (CHCl₃ ; 25° C; 0.40g/dl). Melting range 292°-300° C Decomposition temperature: 320° C. Thepolymer could be cast from a chloroform solution into a colourlessflexible film which was non-burning.

EXAMPLE 6: Preparation of polyamide IX.

To 0.025 mole (7.935 g of phosphoric dipropylamido bispiperazidotriamide and 0.05 mole (2.80 g) of potassium hydroxide in 200 ml ofwater was added with vigorous stirring, 0.025 mole (5.332 ml) ofsebacoyl chloride dissolved in 200 ml of carbon tetrachloride, and themixture was stirred for 30 minutes. The precipitated polymer wasfiltered off and dissolved in 250 ml of chloroform, and this mixture waswashed with water. Chloroform was stripped off and after addition of 50ml of benzene and 50 ml of ethanol, the rest of the water and thesolvents were stripped off, and the residue was sucked dry under vacuum(0.5 mm). The polyamide was obtained as a hard, white foam. Yield: 28.5g (78.57%); [η] = 0.425 dl/g; η_(red) = 0.44 dl/g (CHCl₃ ; 25° C; 0.40g/dl). Melting Temperature 170° C. Decomposition temperature 300° C. Thepolymer could be cast from a chloroform solution into a colourless,flexible film, which was self-extinguishing.

EXAMPLE 7: Preparation of polyamide X

To 0.005 mole (1.196 g) of sebacoyl chloride dissolved in 65 ml ofchloroform was added, at room temperature with stirring, 0.005 mole(1.392 g) of ethyl bispiperazidothiophosphate and 0.012 mole ofpotassium hydroxide in 60 ml of water. The mixture was stirred at roomtemperature for 2 hrs., an additional amount of 80 ml of chloroform and20 ml of water was added, the chloroform layer was separated and thewater layer was extracted once with chloroform. The collected chloroformsolutions were water washed; and the solvent and the rest of the waterwas stripped off under vacuum.

Tthe crude polymer was redissolved in 30 ml of chloroform; the solutionwas filtered and poured into 400 ml of petroleum ether. The precipitatedpolymer was filtered off and dried. Yield: 2.164 g (97.3%); [η] = 0.40dl/g; η_(red) = 0.425 dl/g (CHCl₃ ; 25° C; 0.40 g/dl). Melting range:230°-250° C; Decomposition temperature 290° C.

The polymer formed a colourless flexible film which wasself-extinguishing.

EXAMPLE 8: Preparation of polyamide VIII

To a solution of 0.005 mole (1.552 g) of phenyl bispiperazidophosphateand 0.012 mole of potassium hydroxide in 40 ml of water is added in oneportion, with stirring, at room temperature, 0.005 mole (1.066 g) ofsebacoyl chloride in 40 ml of carbon tetrachloride, and the mixture wasstirred for 15 minutes, during which the swollen polymer formed onelump. The polyamide was washed with water, dried over P₂ O₅ in vacuo at60° C., redissolved in chloroform and precipitated by petroleum ether.Yield: 2.047 (85.9%); [η] = 0.80 dl/g; η_(red) = 0.88 dl/g (CHCl₃ ; 25°C; 0.40 g/dl); melting range: 173°-180° C; decomposition temperature260° C.

The polymer could be cast from a chloroform solution into a colourless,flexible film which was non-burning.

Although this invention has been illustrated by reference to specificembodiments, it will be apparent to those skilled in the art thatvarious changes and modifications may be made which clearly fall withinthe scope of this invention.

What we claim is:
 1. A solid polymer consisting essentially of repeatingunits of the formula ##STR21## wherein (i) X is oxygen or sulfur or═N--R and a is 0 or 1;(ii) Y represents an aliphatic, cycloaliphatic, oraromatic hydrocarbon group; or --OR; or --NR₂, other than dimethylamino;or --NR₂ in which the two R groups, together with the nitrogen atom towhich they are attached, represent an N-containing heterocyclic ring; ora group of the formula ##STR22## wherein R, R¹, R², and R³ representhydrogen or an aliphatic, cycloaliphatic, or aromatic hydrocarbon group;(iii) R⁴ represents hydrogen or an aliphatic group, a cycloaliphaticgroup, an acyl group, or an unsubstituted carbamoyl group; (iv) n¹, n²,and n³ each represent 0 or an integer; (v) Z represents ##STR23## (vi)R⁵ represents an aliphatic, cycloaliphatic, or aromatic hydrocarbongroup.
 2. A solid polymer as claimed in claim 1 wherein n¹ and n² arezero.
 3. A solid polymer as claimed in claim 1 wherein a is 1 and Yrepresents alkoxy, aryloxy, or dialkylamino.
 4. A solid polymer asclaimed in claim 1 wherein Z represents a diacyl radical derived from analiphatic or aromatic dicarboxylic acid.
 5. A solid polymer consistingessentially of repeating units of the formula ##STR24## wherein (i) X isoxygen or sulfur(ii) Y represents an aliphatic, cycloaliphatic, oraromatic hydrocarbon group; or --OR; or --NR₂, other than dimethylamino;or --NR₂ in which the two R groups, together with the nitrogen atom towhich they are attached, represent an N-containing heterocyclic ring; ora group of the formula ##STR25## wherein R and R³ represent hydrogen oran aliphatic or cycloaliphatic or aromatic hydrocarbon group; (iii) R⁴represents hydrogen or an aliphatic group, a cycloaliphatic group, anacyl group, or an unsubstituted carbamoyl group; and (iv) n³ representszero or an integer.
 6. A solid polymer consisting essentially ofrepeating units of the formula ##STR26## wherein (i) X is oxygen orsulfur;(ii) Y represents an aliphatic, cycloaliphatic, or aromatichydrocarbon group; or --OR; or --NR₂, other than dimethylamino; or --NR₂in which the two R groups, together with the nitrogen atom to which theyare attached, represent an N-containing heterocyclic ring; or a group ofthe formula: ##STR27## wherein R and R³ represent hydrogen or analiphatic of the cycloaliphatic or aromatic hydrocarbon group; (iii) R⁴represents hydrogen or an aliphatic group, a cycloaliphatic group, anacyl group, or an unsubstituted carbamoyl group; (iv) n.sup. 3represents zero or an integer; and (v) R⁵ represents an aliphatic,cycloaliphatic, or aromatic hydrocarbon groups.
 7. A solid polymerconsisting essentially of repeating units of the formula: ##STR28##
 8. Asolid polymer consisting essentially of repeating units of the formula:##STR29##
 9. A solid polymer consisting essentially of repeating unitsof the formula: ##STR30##
 10. A process for the production of a solidpolymer as claimed in claim 1 which comprisesreacting a bispiperazide ofthe formula: ##STR31## with a reactive derivative of an acid, saidderivative having the formula:

    R.sup.7 -- X-- R.sup.8

wherein Z is ##STR32## and R⁷ and R⁸ represent halogen, hydroxy, oralkoxy.
 11. A process for the production of a solid polymer as claimedin claim 10 which comprisesreacting a bispiperazide of the formula##STR33## with ##STR34##
 12. A process for the production of a solidpolymer as claimed in claim 10 which comprisesreacting a bispiperazideof the formula ##STR35## with ##STR36##